Mobile phones, tablets, personal digital assistants (PDA), small-sized portable personal computers and the like are popularized. These electronic devices have a display panel and an operation input panel that is formed integrally with the display panel as one piece.
The operation input panel can detect a touch position on its surface where a user touches, and generates a sensing signal as a change of capacitance, for example. The sensing signal is supplied to a touch signal processing integrated circuit (IC) which is designed to exclusive use for the operation input panel. The touch signal processing IC processes the sensing signal using a computational algorithm prepared in advance, and converts the user's touched position into coordinate data then output it.
As manufacturing technology is developed, the display panel is increased in resolution and size. Accordingly, the operation input panel is required to sense a position with high resolution. The operation input panel is also required to process data input thereto at high speed depending on applications. Furthermore, a device capable of easily changing an application is desired.